Chetan- your RO's approach to PEG placement is definitely ok! That's the approach that I took and I just have a few of my own toughts to share: I was through 4 weeks of chemo-rad when my swallow gave out on me - the swelling in my throat increased to the point that all fluid was trapped in my throat while swallowing (rather than going down) and then squirted back up my throat after each swallow causing choking. That was a Sunday night and from that night on I couldn't even swallow water - I saw my MO the next morning and was scheduled for a PEG on Wed - I had to go to the chemo floor for IV hydration that mon and tues to keep me going til the PEG could be placed. I was pretty bummed about it all - I had thought I was doing so well - making it through week 4 with only 2 weeks to go - I had already thought in my mind that I was going to make it without a tube!

My advice to you is to increase your awareness of your swallow now so that you can be in-tune with changes - the primary reason that MD's advocate for PEG beforehand is that it is a certainty that you WILL have trouble swallowing - the uncertatinty is to what degree - will it be to the point that you can't swallow at all or just to the point that adequate nutrition/hydration is a worry.
The concern with getting it midway is that you're compromised by treatment, you're nutrionally compromised (otherwise you wouldn't be scheduling a feeding tube) and it's hard to jump another hurdle in that condition. All that being said, knowing now that I did need the tube - I still wouldn't have opted to have it placed before treatment - for me, the shorter amount of time with it in place the better.
Good luck to you- you're a strong and intelligent Patient!